1. Field of the Invention
The present invention relates to the field of electronic devices. More specifically, the present invention is directed to a device and method for determining the distance between an object and a device of varying location, such as a motor vehicle.
2. Description of the Related Art
In order to facilitate reversing and to prevent collisions with parked vehicles, or other objects in the way, it is known to provide on the rear of the motor vehicle sensors which, for example, transmit ultrasonic or radar signals and which receive radiation reflected by the obstacle. In this case, the distance between the sensor arranged on the motor vehicle and the obstacle is determined from the propagation time of the signal from the sensor to the obstacle and back again.
DE 40 23 538 A1 discloses a method of generic type in which the distance between an obstacle and a motor vehicle is measured in a contactless fashion. In this case, two ultrasonic sensors are arranged at a prescribed spacing, and a device is provided for evaluating the propagation times between the transmission of in each case one ultrasonic signal and the reception of a reflected ultrasonic signal of respectively the same and the other ultrasonic sensor. The distance is determined in this case using the triangulation principle.
From 197 11 467.9, the measured data obtained from the direct measurement (the sensor transmitting the signal receives the reflected signal) and the measured data obtained by an indirect measurement (a second sensor receives the reflected signal) are compared, and the distance is calculated for the position which was determined by the two measuring methods.
This method has the disadvantage that results of different accuracy are also obtained due to the use of different measuring methods, since measured data which cannot be evaluated are generated with each measuring operation.
It is therefore one object of the present invention to specify a method for determining the perpendicular distance of the object from a motor vehicle, which permits an accurate result of the distance measurement in conjunction with a minimum evaluation time.
Other objects and advantages of the present invention will be apparent from the following summary and detailed description of the preferred embodiments.